According to a theory advanced by researcher Paul Martin，the wave of species extinctions that occurred in North America about 11,000 years ago，at the end of the Pleistocene era，can be directly attributed to the arrival of humans，i.e.，the Paleoindians， who were ancestors of modern Native Americans. However，anthropologist Shepard Krech points out that large animal species vanished even in areas where there is no evidence to demonstrate that Paleoindians hunted them.Nor were extinctions confined to large animals： small animals，plants，and insects disappeared，presumably not all through human consumption. Krech also contradicts Martin's exclusion of climatic change as an explanation by asserting that widespread climatic change did indeed occur at the end of the Pleistocene. Still，Krech attributes secondary if not primary responsibility for the extinctions to the Paleoindians，arguing that humans have produced local extinctions elsewhere.But，according to historian Richard White，even the attribution of secondary responsibility may not be supported by the evidence. White observes that Martin's thesis depends on coinciding dates for the arrival of humans and the decline of large animal species，and Krech，though aware that the dates are controversial，does not challenge them；yet recent archaeological discoveries are providing evidence that the date of human arrival was much earlier than 11,000 years ago. 　3. In the last sentence of the passage， the author refers to “recent archaeological discoveries” (lines 27-30) most probably in order to 　　(A) Refute White's suggestion that neither Martin nor Krech adequately account for Paleoindians' contributions to the Pleistocene extinctions 　　(B) Cast doubt on the possibility that a more definitive theory regarding the causes of the Pleistocene extinctions may be forthcoming 　　(C) Suggest that Martin's， Krech's， and White's theories regarding the Pleistocene extinctions are all open to question 　　(D) Call attention to the most controversial aspect of all the current theories regarding the Pleistocene extinctions 　　(E) Provide support for White's questioning of both Martin's and Krech's positions regarding the role of Paleoindians in the Pleistocene extinctions 老师，我在做这道题的时候，首先定位到最后一句觉得没说什么重点，就有个yet转折，可能这是用来驳斥前面的某些观点的。所以看选项找有没有驳斥的意思的， 发现5个选项全都在驳斥。。。心里慌了往前找。再回去找的时候时间已到。我就随便选了个B（时间一到各种混乱），因为在做这篇文章之前，我大体看了下原文，记住了原文讲的是P反驳M，W反驳P。后来答案我也看明白了，我认为我做这道题的思路出现了偏差，我想问一下应该怎么修正。

请数学老师讲解 什么叫整数角？没有小数点的不都是整数角吗？我已经忘了勾股定理了 这个题怎么确定？

请数学老师讲解思路，抛物线上的y轴交点为什么是3？一些基础知识我也忘了，请老师一起说下，谢谢。

请数学老师讲解下 这里面的思路我不太明白 第三次落地是不是就加到0.73二次方x 我每次都计算出800

请数学老师讲解 这个条件1我懂。条件2计算量好大。有什么快点的方法

请数学老师讲解思路，根号10我也只能估算出是3.a 感觉计算量好大 短时间完不成

请数学老师讲解下 谢谢

请数学老师解答下思路。为什么截距是2方程就是可以设为y=k(x-2)

请数学老师帮我讲下这类题的思路

还请金老师帮忙解答，谢谢，在讲现在分词的作用时，有两个句子：please answer the question using another way及look at the people lying on thethe beach.不是说现在分词不能做谓语，这两个句子的主谓结构能帮忙分析下吗，谢谢

王文静老师您好，这套题目我不太懂选项B红色字体部分为什么不对，然后released in 2009，这里面的released是动词还是形容词？bringing、winning的造句为什么不对？这道题的考点是哪个？非常感谢